1. Field of the Invention
The present invention relates generally to refrigeration equipment, and more specifically to a system for analyzing currently performing refrigeration equipment.
2. Description of the Prior Art
The general performance parameters of refrigeration equipment are well known, and the industry currently has various means to monitor and evaluate the performance of such equipment, including means involving computers.
A recent standard by the Air-Conditioning and Refrigeration Institute (ARI Standard 550/590, effective 1998) encompasses the performance principles of refrigeration equipment in the context of water-chilling packages using the typical vapor compression cycle. This standard, as it currently reads, is incorporated herein by reference, as if set forth herein verbatim.
From industry practice and the standard it is clear that a primary performance characteristic of a water-chiller package is the amount of power required to generate the appropriate evaporator tonnage, since the product of the evaporator is the chilled water which is routed for specific cooling tasks to other parts of the location, e.g. the offices and rooms. The prior art includes several examples of monitoring the actual power requirements for a given evaporator tonnage. For example, U.S. Pat. No. 5,083,438, by McMullin, issued in 1992, provided a system to monitor the performance of a water-chiller package, including examining its actual power requirements in light of its own design rated power requirements.
While the McMullin approach and other approaches may be suitable for the purposes for which they were designed, they would not be as suitable for the purposes of the present invention, as hereinafter described.
What is lacking in the prior art with respect to monitoring refrigeration packages, such as water-chilling packages, is the ability to assess the economic impacts of the existing performance against the chiller""s own deign performance and the hypothetical performance of other chillers under the conditions existing at the time the existing chiller package is being evaluated. It is to the advantage of the operator, or owner, of such a water-chiller package to have a system that would monitor the water-chilling package, compare its power usage performance to its own design ratings, as well as, the design ratings of other chillers, that might be used to replace the one in operation. Such an economic comparison would enable the operator to make informed decisions as to the need to replace the existing water-chilling package with a different one, based on an analysis of how the prospective package would have performed under actual, historical operating conditions. Furthermore, current monitoring systems do not provide the communication of possible causes of, and potential solutions to, unsatisfactory conditions that are ascertained during the monitoring process.
My invention provides a system, including computer hardware, computer software, and related apparatus, that assesses the economic impacts of the existing chiller performance against the chiller""s own design performance and the hypothetical performance of other chillers under the conditions existing at the time the existing chiller package is being evaluated. The operator is provided a system that monitors the water-chilling package and compares its power usage performance to its own design ratings, as well as, the design ratings of other chillers that might be used to replace the one in operation. Such an economic comparison enables the operator to make informed decisions as to the need to replace the existing water-chilling package with a different one, based on an analysis of how the prospective package would have performed under actual, historical operating conditions. My system also provides the communication of possible causes of, and potential solutions to, unsatisfactory conditions that are ascertained during the monitoring process.
My invention includes a method for economically analyzing the performance of an operating first chiller with respect to the hypothetical design rated performance of at least one other chiller, the method comprising the steps of: (a) for the first chiller and for each of at least one designated time periods, obtaining at least one set of real tonnage derivation data, real power usage data, and cost per unit of power data; (b) obtaining other chiller information, including design rating information for each of the other chillers, the design rating information including the design rated power requirement; (c) deriving the power cost difference to operate the first chiller compared to at least one of the other chillers; and (d) economically differentiating the future use of the first chiller with respect to the hypothetical future use of the at least one other chiller.
My invention also includes a method for analyzing the performance of an first chiller with respect to the hypothetical design rated performance of at least one other chiller, the method comprising the steps of: (a) for the first chiller and for each of at least one designated time periods, obtaining real power usage data and at least one set of real tonnage derivation data; (b) obtaining other chiller information, including design rating information for each of the other chillers, the design rating information including the design rated power requirement; (c) deriving the power requirement difference to operate the first chiller compared to at least one of the other chillers; and (d) differentiating the future use of the first chiller with respect to the hypothetical future use of the at least one other chiller, based on the power requirement difference.
My invention also includes a method for analyzing the performance of an operating chiller, the method comprising the steps of: (a) for the operating chiller and for each of at least one designated time periods, obtaining real power usage data and at least one set of real tonnage derivation data; (b) obtaining design rating information for the operating chiller, the design rating information including the design rated power requirement; (c) for the operating chiller, deriving a representative evaporator tonnage for each designated time period, from the real tonnage derivation data for such designated time period; (d) for the operating chiller, deriving the actual power requirement from the representative evaporator tonnage and the real power usage data; and (e) differentiating the actual power requirement for the operating chiller with respect to the design rated power requirement for such chiller. This method also comprises the step of communicating the results of the power requirement differentiation, including, if the actual power requirement is unsatisfactory when compared to the design rated power requirement, communicating an indication that an unsatisfactory condition exists; and also communicating suggestions as to potential causes of and solutions to the unsatisfactory condition. The satisfactory determination can be based on operator selected tolerance ranges.
My invention also includes a method for economically analyzing the performance of an operating first chiller with respect to the hypothetical design rated performance of at least two other chillers, the method comprising the steps of: (a) for the first chiller and for each of at least one designated time periods, obtaining at least one set of real tonnage derivation data, real power usage data, and cost per unit of power data; (b) obtaining other chiller information, including design rating information for at least two of the other chillers, the design rating information for each of the at least two chillers including the design rated power requirement; (c) deriving the power cost difference to operate the first chiller compared to the operation of at least one sequenced combination of at least two of the other chillers; and (d) economically differentiating the future use of the first chiller with respect to the hypothetical future use of the at least one sequenced combination of the at least two other chillers. This method also comprises the step of inputing the selection of the at least two other chillers in the combination, including the order in which the at least two other chillers in the selected combination will be utilized in operation.
My invention includes a computer readable medium containing program instructions for execution on a computer system, which when executed by a computer, cause the computer system to perform all the above method steps.
My invention also includes means for performing all the above method steps.
In the description reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration, specific embodiments in which the invention may be practiced. These embodiments will be described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is best defined by the appended claims.